How to animate elements of a UIStackView that’s created in a separate function - swift

Question

I'm trying to animate a stackview and its elements upon pressing a UIButton. the problem is that the stackview is created inside a function which is called in viewdidload.
Because the stackview is created inside a function I cannot call it inside the function that manages the animation... I think i'm doing something wrong...
my stackview creation function
fileprivate func variableContent() {
let stackviewButtons = UIStackView(arrangedSubviews: [registerSerialNumberButton, dothislaterButton])
stackviewButtons.axis = .vertical
stackviewButtons.alignment = .fill
stackviewButtons.spacing = 10
let stackview = UIStackView(arrangedSubviews: [registerTitlelabel, registerdescriptionLabel, serialnumberInput, stackviewButtons])
stackview.axis = .vertical
stackview.spacing = 20
stackview.setCustomSpacing(40, after: registerdescriptionLabel)
stackview.setCustomSpacing(100, after: serialnumberInput)
view.addSubview(stackview)
stackview.anchor(top: nil, left: view.leftAnchor, bottom: nil, right: view.rightAnchor, paddingTop: 0, paddingLeft: 20, paddingBottom: 0, paddingRight: 20, width: 0, height: 0)
stackview.centerXInSuperview()
stackview.centerYInSuperview()
}
viewdidload
override func viewDidLoad() {
variableContent()
}

Answer 1

You can return the stackview from your function and keep a reference to it as an instance variable. That way you can reuse it later.
class Controller: UIViewController {
var stackView: UIStackView!
fileprivate func variableContent() -> UIStackView {
let stackviewButtons = UIStackView(arrangedSubviews: [registerSerialNumberButton, dothislaterButton])
stackviewButtons.axis = .vertical
stackviewButtons.alignment = .fill
stackviewButtons.spacing = 10
let stackview = UIStackView(arrangedSubviews: [registerTitlelabel, registerdescriptionLabel, serialnumberInput, stackviewButtons])
stackview.axis = .vertical
stackview.spacing = 20
stackview.setCustomSpacing(40, after: registerdescriptionLabel)
stackview.setCustomSpacing(100, after: serialnumberInput)
view.addSubview(stackview)
stackview.anchor(top: nil, left: view.leftAnchor, bottom: nil, right: view.rightAnchor, paddingTop: 0, paddingLeft: 20, paddingBottom: 0, paddingRight: 20, width: 0, height: 0)
stackview.centerXInSuperview()
stackview.centerYInSuperview()
return stackview
}
override func viewDidLoad() {
super.viewDidLoad()
self.stackView = variableContent()
}
}
An other option would be to give it a tag (stackview.tag = 42)
and recover it with self.view.viewWithTag(42)

Answer 2

In addition to Marcio's answer, you can also declare the stackView optionally and set it in the function:
class Controller: UIViewController {
var stackview: UIStackView?
fileprivate func variableContent() {
let stackviewButtons = UIStackView(arrangedSubviews: [registerSerialNumberButton, dothislaterButton])
stackviewButtons.axis = .vertical
stackviewButtons.alignment = .fill
stackviewButtons.spacing = 10
self.stackview = UIStackView(arrangedSubviews: [registerTitlelabel, registerdescriptionLabel, serialnumberInput, stackviewButtons])
stackview.axis = .vertical
stackview.spacing = 20
stackview.setCustomSpacing(40, after: registerdescriptionLabel)
stackview.setCustomSpacing(100, after: serialnumberInput)
view.addSubview(stackview)
stackview.anchor(top: nil, left: view.leftAnchor, bottom: nil, right: view.rightAnchor, paddingTop: 0, paddingLeft: 20, paddingBottom: 0, paddingRight: 20, width: 0, height: 0)
stackview.centerXInSuperview()
stackview.centerYInSuperview()
}
// Whatever your animating function is:
func animateStackView() {
guard let stackview = self.stackview else { return }
// You now have access to your stackView for the rest of this function.
}
}
Note: For consistency with your question, I kept the name of the UIStackView as stackview in the code, but according to Swift naming conventions, you should name variables in camelcase (stackView)